The invasion of the Western honey bee, Apis mellifera, by Varroa
destructor is attributed to two mitochondrial haplotypes (K and J) that shifted
last century from their primary host the Eastern honey bee, A. cerana, in
north-east Asia. Here, mitochondrial DNA sequences (cox1,
cox3, atp6 and cytb: 2700 base pairs)
were obtained from mites infesting both Eastern and Western honeybees (respectively 21 and
11 colonies) from Asia including regions where the shifts first occurred. A total of
eighteen haplotypes were uncovered in Asia (11 on A. cerana and 7 on
A. mellifera). Two new variants of the K haplotype and two of the J
haplotype were found on Western honeybees in what appeared to be well-established
infestations. New haplotypes may represent a potential threat to A. mellifera
worldwide. The extreme lack of polymorphism in the K and J haplotypes outside of
Asia, can now be plausibly explained as being due to genetic ‘bottlenecks’ that occurred
in Asia before and after mites shifted from their original Eastern honeybee host.